550 SCIENTIFIC RECORD FOR 1883. 



The times of occurrence of maxima and minima, and the amplitudes, 

 especially of the variations in declination, correspond very closely to the 

 distance of the stations from the auroral circle surrounding the mag- 

 netic north pole, as late'y defined by Baron Nordcnskiold ; hence it 

 would seem to follow that in this circle originate both the aurora and 

 the magnetic declinations. Wild concludes that the source of the per- 

 turbing forces is so far distant that these are essentially parallel for 

 all stations, and that possibly, in magnetic perturbations, the total mag- 

 netic force of the earth is not changed, but the increase at some stations 

 is compensated by diminution at others ; so that the perturbing forces, 

 as it were, merely push over or disarrange the geographical distribu- 

 tion of terrestrial magnetism. He finds evidences of the existence of 

 several independent points in the auroral circle, whence originate the 

 magnetic disturbances that were felt in Europe. (Z. 0. G. M., xvm, 

 p. 97.) 



Lemstrom having observed that in Spitzbergen the galvanometer 

 needles had distinctive motions during au aurora when he held it aloft 

 in his hands, took occasion, on his subsequent expedition to Lapland, to 

 establish a staff with metallic point upright on a hill 150 meters high, and 

 connected the point by insulated wire with his galvanometer 4 kilometers 

 distant, and thence to the ground plate of platinum buried a half meter 

 in the earth. Beams of light (the elementary light-needles of the aurora) 

 appeared at night over the hill, and the motion of the galvanometer 

 needle, whenever the circuit was closed, showed the presence of a gal- 

 vanic current. Lemstrom proposes further investigation of the phe- 

 nomena in northern regions, but also deems it proper to recommend 

 this to the attention of observers in temperate latitudes, where auroras 

 are frequent. (Z. 0. G. M., xvn,p. 115.) 



Prof. R. Robinson has published his long-promised second part of his 

 catalogue of auroras observed from 1700 to 1877 in Sweden, concerning 

 which Professor H. Fritz remarks, that it is the conclusion of a labor of 

 the highest importance in this department, especially in that it gives 

 the fullest possible details as to time, place, details and authorities 

 for each aurora. The total number of aurora days is 7,780: the epochs 

 of maxima follow the sun-spot maxima at an average interval of 14 years. 

 The annual periodicity shows the dependence on latitude already devel- 

 oped by Weyprecht and Tromholt and others, viz, the most northern 

 stations show a decided maximum in the winter months, whereas at tem- 

 perate latitudes this subsides iuto two maxima at the respective equi- 

 noxes. (Z. O. G. M., xvn, p. 441.) 



Prof. H. Fritz presents an interesting analysis of the chronological 

 list of auroras compiled by Lieut. A. W. Greely, of the Army Signal 

 Office, which he recognizes as a valuable contribution of data especially 

 towards the determination of the daily and secular periodicity. He 

 finds sufficient confirmation from the long series of observations at To- 

 ronto, Gardiner, Cambridge, and Willets Point, &c, of the agreement 

 between the periodic variations of the "aurora with the variation of the 





